An organic thin film transistor (OTFT) is a semiconductor device produced by replacing a conventional inorganic material with an organic material. Compared to a transistor made from an inorganic material, OTFT has more and newer film forming technologies, so that the production process is simple, diversity and low cost, and the manufactured transistor is more flexible.
Silicon oxide is a very important insulating material in silicon-based semiconductor devices and its preparation process is mature, and thus, in an existing configuration of the organic thin film transistor illustrated in FIG. 1, silicon oxide is usually used as an insulating layer 12 on a gate electrode layer 11, afterwards, a source/drain electrode layer 13 is fabricated on the insulating layer 12, and an organic semiconductor material is printed on the source/drain electrode layer 13 to form an organic semiconductor layer 14.
As regards existing processes for fabricating organic thin film transistors by inkjet printing, the majority of them are to print an organic semiconductor ink material on a silicon oxide substrate directly. As the crystallization property of the organic semiconductor material is different between a surface of silicon oxide and a surface of metal electrode, it leads to a discontinuity of an organic semiconductor thin film on the boundary of a channel. Thus, the need of printing a continual organic semiconductor thin film across the channel cannot be satisfied, and eventually, continuity of the organic semiconductor thin film will be destroyed, and the crystal configuration of the organic semiconductor thin film will be uncontrollable. Furthermore, from the point of view of device performance, in case that the organic semiconductor material is directly printed on the silicon oxide substrate, an obvious hysteresis phenomenon presents in its transmission characteristic.